The present invention pertains to the communication art and, in particular, to a means for switching an antenna to either a transmitter or a receiver.
Antenna switching systems are well known in the communication art. Such systems are commonly used in transceivers wherein a transmitter and receiver share a common antenna. The antenna switch must not only provide a means for routing the antenna to either the transmitter or the receiver, but it must also isolate the transmitter from the receiver such that, for example, in the transmit mode the receiver is not overloaded by the transmitted signal.
One prior art approach to antenna switching is the use of an electromechanical switch or relay. Such relays are not only expensive, but are also bulky and, thus, not ideally suited for limited space applications such as mobile transceivers. A further approach has been the use of PIN diodes in a biasing scheme whereby the diodes either connect or disconnect the receiver or transmitter to the antenna. The PIN diode switching schemes are expensive due to the cost of the diodes, and are generally complex to implement due to the sophisticated biasing scheme needed to properly control the diodes.